Listing 3: Stack to hold expression objects

class  ExpStack
    {
    private:
        struct  node
            {
            Exp_Obj  *data;
            node  *next;
            };
        node  *head;
    public:
        ExpStack(  void  )  {  head=NULL;  };
        ~ExpStack(  void  )
            {
            node  *temp;
            while  (head!=NULL)
                {  temp=head;       head=head->next;      delete  temp;  }
            }
        void  Push(Exp_Obj  *obj)
            {
            node  *temp=new  node;
            temp->data=obj;    temp->next=head;
            head=temp;
            };
        Exp_Obj  *Pop(  void  )
            {
            if  (head==NULL)
                {
                cout  <<  "Stack  Underflow...\n";
                exit(1);
                }
            node  *temp=head;
            head=head->next;
            Exp_Obj  *tempData=temp->data;
            delete  temp;
            return  tempData;
            };
        int  Empty(  void  )  {  if  (head==NULL)  return  1;  else  return  0;  }
    };
/* End of File */